The U.S. Army reported Sunday that Pfc. Andrew Sass was killed at the National Training Center at Fort Irwin, about 150 miles east of Bakersfield. Lt. Col Joe Sowers says Sass died Saturday and has declined to disclose details, saying the incident was still under investigation.

The 23-year-old soldier was from Fremont, North Carolina, and assigned to Company C, 2nd Battalion, 1st Infantry Regiment at Joint Base Lewis-McChord near Seattle. Sass was on a monthlong training mission at Fort Irwin.